This invention generally relates to cardiac mapping, more particularly to electrode sets and assemblies for conducting epicardial and/or endocardial mapping. In an important aspect of this invention, the electrode set is arranged in a manner such that the configuration of the set will generally conform to the portion of the heart that is being mapped, including generally convex and concave portions such as the apical portion thereof. In another important aspect of the mapping electrode assembly according to this invention, the electrodes are provided in a symmetrical array such that the assembled electrode set can be rotated by a predetermined angular amount, for example 60.degree., without substantially varying the electrode pattern.
Mapping electrode sets for epicardial and endocardial mapping of heart signals have been provided in the past. Typically, these mapping electrode sets are utilized during cardiac surgery in order to sense the cardiac signal and report it to the surgical team through appropriate display and/or print out devices. The surgical team may observe the reported data and immediately utilize same in connection with a surgical procedure, or the data may be collected for subsequential analysis. Such mapping involves timing that is based upon the leading edge of an excitation wave through conductive tissue of the heart. Generally, mapping procedures include the induction of tachycardia while the mapping electrode set is in place, which means that mapping speed and efficiency is extremely important during these procedures.
One characteristic of a mapping electrode set that can interfere with mapping speed and efficiency is the inability of the electrode set to be manipulated such that electrodes are positioned at the desired cardiac location. In the past, the electrodes of a mapping set typically have been generally stationarily mounted with respect to each other, whereby it is not possible to substantially modify the mapping surface to which the electrodes are mounted. Many such mapping surfaces are generally flat, and it is not possible to simultaneously engage all of the electrodes of such a mapping surface with a concave or convex tissue surface being mapped. Even when such electrode sets are mounted into a mapping surface having a generally curved configuration, the particular curved configuration does not always adequately conform to the concave or convex tissue surface to which it is applied, with the result that all of the electrodes needed by the surgeon cannot simultaneously contact the cardiac tissue being mapped. For example, a substantially flat electrode set cannot be satisfactorily used for mapping the apical portion of the heart. Non-contact of an electrode contributes to inadequate data being reported relative to the time and the direction of propagation along and activation of a particular pathway. If the tissue area being mapped is generously curved, such as in an apical region of the heart, this non-contact of electrodes will often prevent any truly useful mapping of such an area.
Also, it often becomes necessary, especially when mapping tissue areas that are difficult to reach, to maneuver the mapping electrode assembly in order to precisely locate same. Such manipulation can be hampered by connector leads and the like of the mapping device, and minimizing the manipulation of the electrode mounting structure that is needed for a particular placement of the electrode set can be advantageous in many instances.
There is accordingly a need for a mapping electrode set assembly that is capable of conforming to the configurations of body organs, particularly the apical area of the heart such that the electrodes can simultaneously contact the heart tissue. It is also desirable to provide a mapping electrode system wherein the electrode set is positioned in a symmetrical array in order to provide a plurality of substantially identical electrode orientations that can be located at a desired position by a minimum of manipulation.